JP3473725B2 - Unit injector mounting structure for diesel engine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diesel engine unit injector mounting structure, and more particularly to a unit injector mounting structure in which a solenoid portion is integrally mounted on an upper portion of a nozzle portion.

[0002]

The magnitude of the normal injector used in the Related Art Diesel engines, in order to displacement of the engine is obtained substantially in proportion, similar to the case of a large engine according scaling law design even in small engine A mounting structure can be adopted . However, in the unit injector that is being adopted as a part of exhaust gas reduction technology, the nozzle size can be made almost proportional to the engine displacement, but due to the current technical restrictions It is difficult to give a difference in the size of the solenoid part almost in proportion.

Therefore, in a large displacement engine, the unit injector can be mounted relatively easily, but in a small displacement engine, the area required for mounting the unit injector with respect to the space above the cylinder head. The ratio of will increase.
Also, it is difficult to fix the unit injector with the solenoid part, and there is no choice but to fix it with the nozzle part, which is normally out of sight, which complicates the mounting structure of the unit injector and improves workability in assembly. And there was a problem that maintainability deteriorated.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a unit injector having an outer diameter and a height larger than those of a normal injector without impairing workability in assembling and maintainability. An object is to provide a mounting structure having a simple structure that can be mounted easily and accurately.

[0005]

In order to solve the above problems, the present invention provides a unit injector in which a step portion substantially parallel to the upper surface of a cylinder head is provided on the outer peripheral surface of a nozzle portion, and a lower surface on the upper surface of the cylinder head. And a clamp having a claw at the tip end that abuts against the upper surface of the stepped portion, and a tightening bolt that is inserted into a bolt hole provided in the clamp to tighten and fix the clamp to the upper surface of the cylinder head. ing. In addition, a tightening flange that sits on the receiving surface provided at the upper edge of the bolt hole is provided in the middle portion of the tightening bolt,
The head of the tightening bolt is located near the upper end of the solenoid part integrally provided on the upper part of the nozzle part, and the inner peripheral surface of the bolt hole is larger than the screw part provided at the tip of the tightening bolt. The valve mechanism and solenoid part are made up of uneven diameter surfaces.
Clamp the tip of the tightening bolt
Insert it into the bolt hole of the
The feature is that it can be hooked on the uneven surface . It is desirable that the bolt hole is formed by a screw hole having a larger diameter than the screw portion provided at the tip of the tightening bolt and having the same pitch as the screw portion.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of a mounting structure for a unit injector of a diesel engine according to the present invention, and FIG. 2 is a sectional view taken along line AA of FIG.

In these figures, the nozzle portion 3 of the unit injector 3 is fitted into the mounting hole 2 provided in the cylinder head 1.
A is inserted from above and its tip is exposed to a combustion chamber (not shown). The unit injector 3 includes a nozzle portion 3a that is inserted into the mounting hole 2 and a solenoid portion 3b that is integrally attached to the upper portion of the nozzle portion 3a. An injection signal is supplied from a controller (not shown). When it is operated, the solenoid incorporated in the nozzle portion 3b is excited to constitute a conventionally known electromagnetic unit injector that opens the nozzle portion 3a.

On the outer peripheral surface of the nozzle portion 3a, there is formed a step portion 4 which is substantially parallel to the upper surface of the cylinder head 1. Then, the lower surface of the bifurcated claw 5a provided at the tip of the clamp 5 whose lower surface is formed substantially parallel to the upper surface of the cylinder head 1 is pressed against the upper surface of the step portion 4 and the clamp 5 is tightened with the tightening bolt 6. The unit injector 3 is fixed by tightening and fixing it to the cylinder head 1. In addition,
By pressing and holding the tightening surface provided at the tip of the nozzle portion 3a against the seat surface (not shown) of the cylinder head 1 by the pressing force of the claw 5a of the clamp 5, the cylinder head 1
The airtightness between the unit injector 3 and the unit injector 3 is secured.

Here, in the present embodiment, the clamp 5
Tightening bolt 6 for tightening and fixing the cylinder to the upper surface of the cylinder head 1.
The head part 6a of the unit to the solenoid part 3 of the unit injector 3
It is located near the upper end of b to ensure the operability of the tightening bolt 6. Then, the bolt hole 5b provided in the clamp 5
Is formed with a screw hole having a diameter larger than that of the threaded portion 6b provided at the tip of the tightening bolt 6 and having the same pitch as the threaded portion 6b to form the concave and convex surface 5c on the inner circumference. 5c and screw part 6
The clamp 5 can be hooked and held on the tip of the bolt 6 by the engagement action of b.

Reference numeral 6c is a tightening flange provided on the tightening bolt 6, and the lower surface of the tightening flange 6c and the bolt hole 5 are provided.
By forming the receiving surface provided on the upper edge of b in a spherical shape, the seating property of the tightening flange 6c is secured. 7
Is a valve mechanism for opening and closing a valve (not shown).

When fixing the unit injector 3 in the mounting structure constructed as described above, the nozzle portion 3a of the unit injector 3 is inserted into the mounting hole 2 of the cylinder head 1 to a predetermined depth. Next, the clamp 5 is placed at a temporary position indicated by a chain double-dashed line in FIG. 1, and the tip end of the tightening bolt 6 inserted through the gap between the valve mechanism 7 and the solenoid portion 3b is inserted into the bolt hole 5b of the clamp 5. Then, the threaded portion 6b of the bolt 6 is hooked on the uneven surface 5c of the bolt hole 5b.

In this way, the screw portion 6b of the tightening bolt 6 is
Is hooked on the concavo-convex surface 5c of the bolt hole 5b, and the head 6a of the tightening bolt 6 is pinched to slightly pull up the bolt 6. Then, since the clamp 5 hooked on the screw portion 6b of the tightening bolt 6 is also pulled up, the clamp 5
Can be easily moved to the normal position shown by the solid line in FIG. 1 and the claw 5a formed at the tip thereof can be superposed on the upper surface of the stepped portion 4 of the unit injector 3. Therefore, after the clamp 5 is moved to the proper position in this way, the head 6a is engaged with an appropriate tightening tool to tighten the tightening bolt 6
The unit injector 3 is fixed to the cylinder head 1 by screwing in the threaded portion 6b .

That is, in this embodiment, the threaded portion 6b formed at the tip of the tightening bolt 6 is hooked on the uneven surface 6c provided in the bolt hole 5b of the clamp 5 to hook the clamp 5 at the tip of the bolt 6. In addition, the head portion 6a of the tightening bolt 6 is located near the upper end of the solenoid portion 3b of the unit injector 3. Therefore, the clamp 5 can be easily and accurately set to a predetermined position via the tightening bolt 6 even in a narrow space where the visibility is insufficient and the operability of the tightening bolt 6 can be secured. Therefore, the unit injector 3 can be easily and accurately attached to an engine with a small displacement in which the installation space for the unit injector 3 is narrow.

In the above embodiment, the bolt hole 5b is formed by a screw hole having a larger diameter than the screw portion 6b provided at the tip of the tightening bolt 6 and having the same pitch as the screw portion 6b.
By making the inner peripheral surface of the concave and convex surface 5c, the clamp 5 can be easily caught by the tightening bolt 6 by utilizing the meshing action of the screw, and the concave and convex surface 5c can be easily formed. It is not necessary to configure the bolt hole 5b .

Further, in the above embodiment, the lower surface of the tightening flange 6c provided on the tightening bolt 6 and the bolt hole 5b.
Although the seating surface of the tightening bolt 6 is ensured by forming the receiving surface provided at the upper edge of the upper surface of the clamp spherical surface, the lower surface of the tightening flange 6c and the receiving surface of the clamp 5 are flat or conical. It can also be configured with.

[0016]

As is apparent from the above description, according to the present invention, the screw portion of the tightening bolt can be hooked on the uneven surface of the bolt hole to move the clamp to a predetermined position. At the same time, since the tightening bolt can be rotated near the upper end of the solenoid of the unit injector,
A unit injector having a larger outer diameter and height than a normal injector can be easily and accurately attached to an engine with a small displacement whose installation space is restricted.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a mounting structure for a unit injector of a diesel engine according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

[Explanation of symbols]

1 cylinder head 2 mounting holes 3 unit injector 3a nozzle part 3b Solenoid part 4 steps 5 clamps 5a nail 5b bolt hole 5c uneven surface 6 Tightening bolt 6a head 6b screw part 6c Tightening flange 7 Valve mechanism

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) F02M 39/00-39/02 F02M 57/02

Claims (2)

(57) [Claims] 1. In a diesel engine in which a unit injector 3 is inserted into a mounting hole 2 provided in a cylinder head 1 from above so that a tip of the unit injector 3 faces a combustion chamber, a step portion substantially parallel to an upper surface of the cylinder head 1. 4 , a unit injector 3 provided on the outer peripheral surface of the nozzle portion 3a ,
A clamp 5 provided abutting pawls 5a at the tip portion on the upper surface of the stepped portion 4 causes face the lower surface to the upper surface of the cylinder head 1, the clamp 5 is inserted into the bolt hole 5b provided in the clamp 5 The cylinder head 1 is provided with a tightening bolt 6 for tightening and fixing, and a tightening flange 6c for seating on a receiving surface provided at the upper edge of the bolt hole 5b is provided at an intermediate portion of the tightening bolt 6 , and the tightening is performed. The head portion 6a of the bolt 6 is located near the upper end of the solenoid portion 3b integrally provided on the upper portion of the nozzle portion 3a , and the inner peripheral surface of the bolt hole 5b is provided at the tip portion of the tightening bolt 6 with a screw portion. 6b, which has a concave-convex surface 5c with a diameter larger than 6b, and clamps the tip of the tightening bolt 6
Threaded portion 6b of the bolt 6 by inserting it into the bolt hole 5b of the bolt 5
Can be hooked on the uneven surface 5c of the bolt hole 5b.
Diesel engine unit injector mounting structure characterized by the above . 2. A threaded portion 6 provided on the tip portion of the fastening bolt 6
2. The unit injector mounting structure for a diesel engine according to claim 1, wherein the bolt hole 5b is formed by a screw hole having a diameter larger than b and having the same pitch as the screw portion 6b .